聚甲醛纤维的制备及其力学性能研究

采用双螺杆熔融纺丝制得聚甲醛(POM)卷绕丝,通过水浴拉伸卷绕制得聚甲醛纤维。利用声速取向测试仪研究了拉伸对纤维取向的影响;利用纤维强度仪测量了纤维的力学性能,研究了拉伸温度、热定形条件、酸碱性环境对纤维力学性能的影响。结果表明:拉伸倍数增大,POM纤维的取向度、断裂强度、模量增大,断裂伸长率减小;控制水浴拉伸温度在80~95℃为宜;紧张热定形有利于提高纤维力学性能。制得的聚甲醛纤维耐碱性优良,有一定的耐酸性能。     

聚甲醛纤维的一步法制备及其性能研究

采用自制的熔融纺丝一体化设备,使用不同熔融指数的聚甲醛的共混料为原料,通过DSC、TGA等测试以及纺丝工艺过程的分析,得出了最佳的原料配比和熔融纺丝工艺。研究了牵伸倍数对聚甲醛纤维拉伸强度的影响,结果表明:在10倍牵伸下,可以制备出拉伸强度为6.2 cN/dtex的聚甲醛纤维。     

聚甲醛纤维的制备与性能

采用熔融纺丝方法,通过调整纺丝工艺参数中的卷绕速度及后牵伸倍数,制备了不同工艺下的聚甲醛(POM)纤维;通过对热性能、取向度和力学性能的测试,分析了POM树脂结晶和降解等热学性能对纺丝过程的影响,同时研究了纺丝工艺参数对POM纤维性能的影响;最后对POM纤维的耐酸碱性能进行了研究。结果表明:POM纤维最佳的纺丝速度为490 m/min,牵伸倍数为7.4。POM纤维的耐碱及耐弱酸性好。     

POM/PBS共混纤维的结构与性能研究

采用聚丁二酸丁二醇酯(PBS)对聚甲醛(POM)进行改性,经共混纺丝制得POM/PBS共混纤维,研究了POM/PBS共混体系的流变行为以及共混纤维的热稳定性、结晶结构和力学性能。结果表明:PBS对POM有一定的增塑作用,可以降低POM的黏度和剪切敏感性;添加PBS可降低共混体系的熔点、结晶温度和结晶度,POM的熔点为168.6℃,结晶温度为145.6℃,结晶度为78.6%,而加入PBS质量分数20%的POM/PBS共混体系的熔点为165.7℃,结晶温度为139.7℃,结晶度为68.9%;PBS增大了POM的球晶尺寸,但PBS质量分数超过15%时,由于发生相分离而产生PBS的环带球晶;当PBS质量分数为10%时,POM/PBS共混纤维力学性能最好,拉伸强度和弹性模量分别达到1 264 MPa,9.5 GPa,相比纯POM纤维分别增加了25.8%和15.9%。     

国内聚甲醛纤维研究进展与应用展望

本文介绍了一种新型高性能纤维-聚甲醛纤维,概述了国内聚甲醛纤维的研究进展,并对其未来市场的应用进行了系统分析,为国内聚甲醛企业扩宽产品下游市场提供一些参考建议.     

高性能聚醚醚酮纤维的制备及性能研究

通过熔融纺丝制备高性能聚醚醚酮（PEEK）纤维,通过优选工艺条件确定螺杆工艺、纺丝组件、纺丝温度、热甬道温度、纺丝速度、牵伸倍数、牵伸温度、牵伸速率等参数,对纤维的线密度及拉伸性能进行测试。结果表明：确定纺丝组件配备为36 f单组分喷丝板、50目/180目/250目/180目/50目五层过滤网以及10目金属过滤砂。当PEEK螺杆挤出机各区温度为350、370、390、400、400、400、400℃,纺丝温度为415℃,热甬道温度为300℃,纺丝速度为200 m/min,牵伸倍数为3.0倍,牵伸温度为200℃,牵伸速率为200 cm/min时,PEEK纤维的线密度为21.33 dtex,PEEK纤维可纺性及力学性能良好。     

熔纺聚乳酸纤维的结构与性能研究

通过熔融纺丝法制备了生物可降解左旋聚乳酸(PLLA)纤维,对纤维进行了拉伸和热定型等后处理,用电子单纤维强力仪和X-射线衍射仪研究了PLLA纤维的力学性能和结晶性能,讨论了纺丝温度、拉伸倍数、定型时间和定型温度等对纤维力学性能的影响。结果表明,当纺丝温度为200℃时,纤维可纺性最好。当拉伸倍数为4倍,热定型温度为60℃,定型时间为30min时,PLLA纤维具有最佳的力学性能,其晶区具有α晶型结构。     

纳米CaCO_3/POM复合纤维的制备

将纳米CaCO3和聚甲醛(POM)按一定的质量比放在超高速混合机中混合,借助混合机叶片高速旋转时产生的热量和外加热的热量,使得POM颗粒软化,再将纳米CaCO3均匀地粘附在其表面上,从而制得聚甲醛复合材料。采用熔融纺丝法制备初生纤维,再通过热空气浴热拉伸得到最终的纤维。最后,通过XRD测试纤维的结晶情况,通过扫描电镜(SEM)测试纤维的表面形态和断面形态以了解纳米CaCO3在聚甲醛基体中的共混情况,通过TG测试纤维的热稳定性和通过纤维工程力学仪器测试单根纤维的力学性能。结果表明:改性和拉伸后纤维的结晶度上升,而晶粒尺寸变小;纤维的表面变得粗糙,低含量的纳米碳酸钙在POM中的分散效果良好;改性后纤维的热稳定性得到明显地提高;纤维的强度和韧性也有较好的改善。     

聚苯乙烯光纤专用树脂的工业开发

根据光纤专用树脂的要求,确定产品的技术指标及生产工艺,开发出聚苯乙烯光纤专用树脂PS 670。与国内光纤专用树脂相对比,PS 670具有优良的加工性能和导光性。加工应用实验表明,PS 670导光性能满足国内光纤生产厂家的质量标准要求,可以进行批量的工业化生产。     

复合纤维(SM-2)改性隔膜的工业化开发

介绍了国产复合纤维(SM-2)改性膜实现工业化的过程，包括扩大工业化、系列工业化及全部工业化。工业化结果表明使用该膜后电流效率提高，隔膜寿命延长，节电效果明显。同时探讨了国产烧结炉的使用效果及存在问题。     

Grafting onto polyformaldehyde fibers

Acrylic acid (AA), acrylonitrile (AN), and acrylamide (AM) were grafted onto polyformaldehyde (PF) fibers employing γ-ray irradiation as well as benzoyl peroxide initiation. The nature of the graft copolymer obtained from a given monomer was dependent on the type of method used for the grafting reactions. This was reflected in the various characteristics of the grafted PF fibers such as moisture regain and dyeability to disperse, direct, basic, and acid dyes. The extent of grafting was dependent on time, concentration of the initiator, concentration of monomer, and irradiation dose. The grafting reaction with all the three monomers and both methods of grafting studied followed first-order kinetics. The rate constant values for grafting with AA, AN, and AM were 0.493, 0.576, and 0.420 hr^?1, respectively for the irradiation method and 0.385, 0.385, and 0.346 hr^?1, respectively, for the benzoyl peroxide initiation technique. The increase in the moisture regain was directly proportional to the amount of graft in the fiber. Acrylic acid grafted PF fibers were rendered hydrophilic to the highest extent (7.9% M.R. for 42% graft), while AM-grafted fibers were rendered so to the lowest extent (7.23% M.R. for 76.5% graft). Considerable improvement in dyeability of PF fibers was observed as a result of grafting. In general, dyeability was proportional to the amount of graft introduced in the fibers. The AA-grafted PF fibers gave a six-to sevenfold increase in disperse dye content when the irradiation method was followed and a four-to fivefold improvement when the chemical method was used during the grafting reaction. The AA-grafted and AM-grafted PF fibers show considerable affinity toward direct cotton dyes. The two substrates could also be dyed with fiber-reactive dyes in deep fast shades, the AM-grafted PF fibers giving deeper shades as a result of higher reactivity imparted to the substrate by the NH₂ group of the graft copolymer. The AA- and AN-grafted PF fibers could be dyed in intense deep shades with cationic dyes. Similarly, AM-grafted substrates gave bright deep shades with acid dyes. Infrared studies, used to analyze the grafted PF fibers, indicated the presence of ? COOH, ? CN, and ? NH₂ groups introduced in the fiber structure as a result of grafting with AA, AN, and AM.     

Electrokinetic properties of polyformaldehyde fibers

Electrokinetic properties, namely, zeta potential (ζ), surface charge density (σ), and surface conductivity (K_s) of polyformaldehyde fibers [poly(oxymethylene) fibers] have been studied in the presence of direct dyes, with or without surfactants and an electrolyte. The anionic dyes increased the negative zeta potential of fibers. The increase in ζ was found to be a function of concentration and basicity of the dye in the streaming solution. Thus, the tetrabasic dye gave higher value of negative ζ than the equivalent concentration of the dibasic dye. The cationic surfactant brought about a decrease in negative ζ, giving a point of inflection, while the anionic surfactant increased it. The nonionic surfactant brought about a certain reduction in negative ζ, but failed to give a point of inflection. In the presence of a direct dye, the cationic surfactant brought about considerable reduction in negative ζ, to give a point of inflection. The presence of an electrolyte in the streaming dye solution progressively lowered the negative ζ. In general, σ increased with the increase in the concentration of either a dye or an electrolyte in the presence of a given concentration of the dye in the streaming solution. Results on K_s indicated that the surface conductivity of the fibers is a function of concentration of dye, surfactant, and electrolyte. It was, however, observed to be independent of the nature of the surfactant. Although both the dibasic and tetrabasic direct dyes brought about an increase in K_s, the extent of increase was dependent upon the basicity of the molecules.     

碳纤维产业现状及发展前景

碳纤维是一种力学性能优异的新材料,被誉为黑色黄金,是指含碳量高于90%的无机高分子纤维。本文主要结合碳纤维的特性及用途,简述了碳纤维的国内外生产现状及我国发展碳纤维产业的措施及建议。